New alkaloids from Forsythia suspensa and their anti-inflammatory activities.

Two new alkaloids, named suspensine A (1) and (-)-7'-O-methylegenine (2), along with two known alkaloids, (-)-egenine (3) and (-)-bicuculline (4), were isolated from the ethanolic extract of the fruits of Forsythia suspensa. Their structures were established by means of chemical methods and spectroscopic analyses. In vitro, four alkaloids showed anti-inflammatory activities, with inhibition rates of release of beta-glucuronidase from polymorphonuclear leukocytes of rats being in the range 34.8%-39.6% at 10 microM.